The invention relates to apparatus for manipulating trays (also known as chargers) for temporary storage of filter rod sections and/or plain or filter cigarettes, cigars, cigarillos and analogous rod-shaped articles of the tobacco processing industry. More particularly, the invention relates to improvements in apparatus for manipulating trays which serve (a) to receive rod-shaped articles from a mass flow of articles between one or more producing and one or more consuming or processing machines, and (b) to admit rod-shaped articles into the mass flow.
Direct coupling of producing (such as cigarette making or filter tipping) machines with processing or consuming (such as packing) machines is becoming an increasing popular mode of transferring large quantities of rod-shaped articles of the tobacco processing industry (see, for example, commonly owned U.S. Pat. No. 4,892,453 granted Jan. 9, 1990 to Bantien et al.). However, and since the output of a single producing machine or the combined output of two or more producing machines does not always match the requirements of the processing or consuming machine or machines, it is necessary to employ so-called buffer stations with equipment which can temporarily store the surplus of the output of the producing machine or machines when the output exceeds the requirements of the associated processing machine or machines, and which can supplement the output of the producing machine or machines when the requirements of the processing machine or machines cannot be met by the maker or makers.
A presently preferred buffer station employs a so-called tray filling or charger filling unit serving to draw rod-shaped articles from the path along which a mass flow of articles advances from the producing machine or machines to the processing machine or machines when the output of the producing machine or machines exceeds the requirements of the processing machine or machines, and a so-called tray evacuating or charger evacuating unit which can discharge the contents of filled trays into the path in order to ensure that the requirements of the processing machine or machines can be met when the output of the producing machine or machines is too low. The buffer station further accommodates a conveyor system or transfer system which serves to transport empty trays from the evacuating unit to the filling unit and to transport filled trays from the filling unit to the evacuating unit. Certain presently known tray evacuating units employ a so-called inverting head (see, for example, U.S. Pat. No. 3,527,369 granted Sep. 8, 1970 to Bornfleth et al..and commonly owned U.S. Pat. No. 4,278,385 granted Jul. 14, 1981 to Bardenhagen et al.) which serves to turn a filled tray through approximately 180.degree. about an axis which is parallel with a longitudinally extending edge of the tray; this entails a change of orientation of rod-shaped articles through 180.degree.. In order to ensure that the orientation of articles which are returned into the mass flow will match the orientation of articles which form the mass flow, it is customary to reorient empty trays on their way from the evacuating unit to the filling unit.
Satisfactory orientation of rod-shaped articles of the tobacco processing industry is important when the articles are filter cigarettes, cigars or cigarillos, i.e., when the articles do not consist of pairs of mirror symmetrical halves. The same holds true if the articles are plain cigarettes which are provided with printed matter, such as the name of the manufacturer, the brand name or the like; the orientation of printed matter on each article in the mass flow must be the same. Therefore, the equipment at the aforementioned buffer station must be capable of ensuring that the orientation of rod-shaped articles (hereinafter referred to mainly as cigarettes or filter cigarettes but with the understanding that the apparatus can be used with equal advantage for the treatment of other types of rod-shaped articles of the tobacco processing industry) which are returned into the mass flow will be the same as the orientation of all other articles in the mass flow.
The tray filling and evacuating units are normally designed to store empty trays at a first level and to store filled trays at a different second level. Reference may be had, for example, to commonly owned U.S. Pat. No. 4,564,329 granted Jan. 14, 1986 to Bantien. Furthermore, the units are equipped with means for transferring trays between the two levels.
A drawback of presently known buffer stations is that the equipment at such stations occupies much space and that the mechanisms which serve to change the orientation of trays are complex and expensive.